Marc, man that's my favorite rifle of all time, looks like you have a real good start, on the blank it looks like you have the pitch of the heel layed out real similar to the original, would be a shame not to do that!
I have one based on that same rifle underway myself - maybe if we both have them at the CLA show in Lexington this Summer we ought to have a shooting match down in the mall
One very interesting feature of that rifle that was not covered in Wallace's fine article - for such a large bore, the rifling is a suprisingly fast twist by "modern" black powder standards. This along with some of the other decidedly Germanic features seems to offer evidence that the gunsmith may have been a German immigrant. The barrel itself seems to generally follow the profile of German barrels of the time, yet stretched over a longer length.
If you (or anybody else reading this) is ever interested in building one with a barrel like the original, I took measurements off it every three inches and took notes on specific changes in profile and gave this to Ed Rayl.